Modern pollen rain analysis from Itapuã State Park (Parque Estadual Itapuã), RS, Brazil.

Itapuã State Park is located in the municipality of Viamão, between the 30º 20 'and 30º 27' S and between 50º 50' and 51º 05' W, in the state of Rio Grande do Sul, southern Brazil. The Park is one of the state conservation units, maintaining remnants of the Atlantic forest, rocky fields vegetation, coastal forest, "vassoural," mixed grassland, moist, bathed and juncal plains. Artificial pollen traps were installed inside the park, between forest and human-modified field. The study presents a morphological description of 34 plant families, represented by 47 different pollen grains and monilophyte spores (including exotic taxa), unpublished data for the park's palinoflora. Quantitative data revealed the presence of 77% of non-arboreal pollen grains, 20% of arboreal pollen grains, 2% of monilophyte spores and 1% of other that can be both arboreal and non-arboreal pollen grains. Non-arboreal pollen grains, especially Poaceae, dominated in all the traps, even those located in forest areas. The dominance of the human-modified fields around collectors and winds from the northeast influenced the dispersion of these grains. Exotic pollen grains of the Betulaceae family, of Andean origin, also occurred in the pollen rain, resulting from dispersion by atmospheric currents of long distances.